The present invention relates generally to broaching tools. More particularly, one form of the present invention relates to a broach tool having a row of removable cutting inserts spaced apart and supported by removable insert support members. Although the present invention was developed for an application involving manufacturing gas turbine engine components, many applications may be outside this field.
Broaching tools have been used for many years for the machining of metallic materials, and for specific operations such as broaching slots, openings or channels in structures. One conventional broaching tool is a unitary broach having a plurality of cutting teeth integrally formed on a cutting bar. Conventional unitary broaches have some inherent limitations in their designs. One limitation associated with the unitary broach integral cutting teeth is that the worst tooth limits the quality of the overall broaching tool. For example, the existence of an undersized cutting tooth results in an overloading of the next tooth, as well as making it often necessary, because of wear or otherwise, to substantially rework the tool or discard the entire tool even though there is still useful life left in many of the other cutting teeth. Historically, damage to one cutting tooth or any one part of the tool has often resulted in the entire unitary broach tool being discarded. Further, the material from which the unitary broach is manufactured has generally been restricted to high-speed steels because of the relatively high cost associated with materials such as carbides.
A second type of conventional broaching tool includes a plurality of separate cutting inserts that are fixed to the tool body. The cutting inserts are typically formed from a carbide material or other hard metal and permanently attached to the tool body in a brazed construction or removably clamped to the tool body by a mechanical clamping structure. Brazed construction broaching tools have generally been limited by failure of the braze joint in the broaching tool manufacturing process or during the utilization of the broaching tool in a manufacturing process of forming an opening in a workpiece. Traditionally, the repair and requalification of a broaching tool is a lengthy and time intensive process.
Although many of the prior broaching tools having cutting inserts clamped to a tool body have been steps in the right direction, there still remains a need for additional improvement. The present invention satisfies this need in a novel and non-obvious way.
One form of the present invention contemplates a broach tool, comprising: a plurality of cutting inserts having a root portion and a cutting portion, the root portion has a base surface and a restraining surface; a carrier including a longitudinally elongated slot defined in the carrier by opposed first and second side walls, a base wall and a top wall, each of the root portions disposed within the longitudinal slot with the base surface located adjacent the base wall and the restraining surface located adjacent the top wall and the cutting portions extending from the carrier; and, an insert support member separable from the carrier and positioned between and longitudinally spacing a pair of the plurality of cutting inserts within the slot, the insert support member extending substantially along the pair of cutting inserts and adapted to reinforce at least one of the pair of cutting inserts during a broaching operation.
Another form of the present invention contemplates a broach tool, comprising: a plurality of broaching inserts having a first retaining portion and a cutting portion; a holder including a longitudinally extending slot defined in the holder, each of the first retaining portions is located within the slot and captured by a portion of the holder, the cutting portion extending from the holder through a longitudinally extending opening in the top wall; and, a plurality of insert support members having a second retaining portion located within the slot and captured by the portion of the holder, one of the plurality of insert support members is located between and longitudinally spaces apart adjacent ones of the plurality of broaching inserts, each of the plurality of insert support members abutting the adjacent ones of the plurality of broaching inserts along a bracing portion, and the bracing portion adapted to reinforce the broaching insert during a broaching operation.
One object of the present invention is to provide a unique broaching tool.
Related objects and advantages of the present invention will be apparent form the following description.